Dry chemical fire extinguisher



2 P. M. CARTER 2,605,848

DRY CHEMICAL FIRE EXTINGUISHER Filed April 28, 1950 2 SHEETSSHEET l INVENTOR. PHIL/P M. CARTER ATTORNEYS.

Patented Aug. 5, 1952 Application April. 28, 1950 sseria1:No."158 ,74-3.-

:The: present invention relate'swto. a novel: and

improved: dry chemicalfire extinguisher viniwhi'ch the dry chemical is maintainedundertipressure and is to be .projectediby pro'pell'antgasz onto the fire-whenthe extinguisher is used;

Objects. and advantages ofthe inventionwill be set. forth in part hereinafterandtin part'w-ill b obviousherefrom or :may 1beJlearnedibypractice with the invention, the" same being realized and attained by-meansof:theinstrumentali- .tiesiand' "combinations? pointediout' in tlre: appended'olaims.

Theiinvention:consistsrinithe :novel parts; constructions, arrangements; combinationsii and .improvementsherein'rshown: and .:described;

The accompanyin'gidrawings; referredrtohereand constituting 'w parthereof, illustrate ;one embodimentpf the invention and rtogetherawith the.adescription:servertoiexplainitheziprincipleszof the invention:.

Qfithe drawings..-

Figure '1 is :a-"side-relevation'of 'aztypical'; illus- JtratiVeFand preferred embodiment-of. theepre- ,ferredinvention; q

Figure :2 is'ia-top' plan view of the: embodiment shown inFigure '1 ;i

I Figure? 3-is a fragmentary-enlargedfront -elevation' ofthe embodiment shown .-.in.-Figures..1 .an'd'2;

Figures. 4 and -5..rare perspectivedetails .of .certain of the parts-.show-nin the ctherifiguresr;

Figure 6. is. a vertioalisection takenon 13116211116 ablegas .under. pressure. Afurther object of the invention. is the provision ofsuch an extinguisher which is more compact, more easily and quickly recharged. and whiclrmay be more rapidl'y'put into .operation than those heretofore developed.

Still another object of the inventioniistheprovision of a lightweight; high. capacity fire extinguisher which isextremely efficient in operation..and which is. instantly available for use in caseof. fire, and .at all times gives a visual indication of 'whetheror not itis ready for service.

Inaccordance with the present invention; there islprovideda dry, chemical. fire extinguisher having a single pressure container which is charged 8::Claims. (Cl.- 169-31) ITO with a;== dry extinguishing powder and a'apropellant gas under relatively high pressure, thereontain'er having an' opening atone end through which it maybe filled with powdersand which may be closed bymeans of a valve and nozzle assembly, the valve controlling the flow of gas and powder-from the container "to the nozzle and normally heldin closed position, ready to be opened when the extinguisher is :to' be .put into service; Associated with thevalve nozzle assembly pressure gauge communicating *withithe zinterior: of. the container showing whether'or' not the container is fully charged with :gas, and 1a relief aperturenormally filled with a:suitableral loy is :providedso as torelease"thelcontentsiof the container in-tthel-event thatiitzbecom'es heated to an excessivev temperaturezsuch..asmight otherwise causethe building up of a dangerous pressure :withinthe container;. The valvemeans comprise :a :plunger valve which is normally I held intseatedzposition by means of 'a'trelatively strong spring; and is liftedfrom its-seat' by meansof a hand lever so that powder rand propellant gas are supplied fromthe "container to theznozzle. In

order. to increase :the effectiveness" of the seating of the valve, and to .preventagainst accidental opening "of the: valve; means are provided forexerting additionalv pressure .on the valve plunger so' as to: maintain itrseated and *tQJrenderIthe handle or valve opening means normally ineffective, the: additional valve seating .meanszbeing quickly releasableyadjustable and normally sealed so'thatthe .operatingihandle canionlybe operated after; the *sea'lihas :been broken; thereby: immediately'indicating that the extinguisher mayh'ave been'nsediand tshould be inspected .orrrecharged. The handle .1 locking and sealing means :is' preferablycin. the form of .aztoggle member mounted on: a'threaded post" which cooperates with a pivoted bail overlying:theplungerand exerting additional pressure on .th'esplunger, the bail being bifurcated and normally holding the a threaded post against turningyandat the same time-securinganut orotherrthreaded member on'the-end of theiplun'ger.

It will be understood that the-foregoingigeneral description" and the following detailed'description as well are exemplary and explanatory of the inventiontbut tare notrestrictive-thereofi Referring now "in detail tto'th'e illustrative: and preferred embodiment of the 'invention'ias :shown in the accompanying drawings, there is'prov'ided a gas and drypowdercylindrical contaiiner Ill, often referred to as a""'bottle. The bottle. is conveniently made as a steel spinning and at its upper end is provided with a threaded aperture l I through which the bottle may be charged with the required quantity of dry extinguishing powder, and thereafter closed by means of the threaded portion I2 of the valved nozzle assembly IA. The valved nozzle assembly is provided with a central cylindrical bore extending axially of the threaded portion l2, and connected to a tube lfi which extends downwardly to near the bottom of the bottle l so as to pick up the dry powder as it is expelled from the bottle through the tube l6 and delivered to the discharge noz zle 18. The valved nozzle assembly is sealed to the bottle ID by means of a suitable sealing ring which prevents escape of gas or powder except through the tube 16 and nozzle l8, and at the same time the sealing ring 20 allows the valved nozzle assembly [4 to be removed from the bottle and replaced thereon after the bottle has been recharged with powder.

In order to prevent injury through accidental opening of the bottle by unscrewing the valved nozzle 14 while the bottle is still under heavy "gas pressure, a bleed hole 22 extends from' the cylindrical bore 24 to the exterior of the threaded portion I2 so that as the valved nozzle assembly I4 is unscrewed from the bottle, any gas pressure remaining in the bottle It] will be discharged to the atmosphere after one or two turns and long before the bottle has been unscrewed from the'assembly. A cylindrical bore 24 at its intermediate portion is of reduced diameter and is provided with an upper face 26 forming a valve seat against which presses a valve closing disc 28, formed of some impervious, slightly resilient material, such as nylon, which is received within a recess in the enlarged end 30 of a plunger-32, the enlarged end 30 substantially filling the enlarged portion 34 of the cylindrical bore, and preventing excessive leakage of gas when the valve is unseated. Plunger 32 is normally pressed downwardly with the valve disc 28 against its seat 26 by means of a relatively heavy helical compression spring 36 received within the recessed end of a retainer 38 which is threaded into the upper end of the cylindrical bore leaving the upper end of the plunger exposed.

Communicating between the cylindrical bore 24 and the nozzle I8 is a passageway 40 delivering to the nozzle It the dry powder suspended in the expanding'propellant gas issuing from the valve. The nozzle l8 comprises a cylindrical member threaded on the exterior of a hollow lateral projection 42, and extending therefrom, being provided with a plurality of apertures 44 which supply the powder and expanding gas to the interior cylindrical end 46 of the nozzle, the gas powder being distributed by means of a conical member 48 supported on a threaded stud 50 in the wall portion 52 of the nozzle so that the propelled powder forms a somewhat conical and more or less hollow stream of powder which may be directed at the base of the fire and even as far away as twenty or thirty feet.

Means are provided for opening the valve and these means comprise a hand lever 60. having an apertured end 62 and a fulcrum portion '64, the slot 62 being adapted to be passed over the end of the plunger 32 and to be retained thereon by means of nut 66, while the fulcrum 64 rests on the upper surface of the flange 3B and provides pivot 64 as the valve is moved to open position,

Means are also provided for exerting addi tional pressure on the valve plunger 32 so as to hold it securely closed, and to prevent accidental opening of the valve, these means serving to exert pressure on the valve plunger 32 in additionto the pressure exerted by the compression spring 36. As embodied, a bail 14 is pivotally mounted between lugs 76 extending upwardly from the assembly I 4, the underside of the bail being channeled, as clearly shown in Figure 4 so that its side members 18 may engage with the sides of the nut 65 and hold it against rotation relatively to the plunger 32. The forward end of the bail I4 is bifurcated, as at 80, providing a slot which fits over a threaded post 82 having fiat sides, the post being threaded into and extending upwardly from the assembly I4, the bailthereby serving to prevent rotation of the post 82 and to hold the post in its desired position of adiustment.

'Means are also provided for locking the bail in its valve closing position, while providing for rapid release of this locking condition. For this purpose a toggle lever 84 is pivotally mounted at 86 on the upper end of the post 82, the toggle lever being formed with a finger engaging portion 83 by which the lever may be instantly moved to unlocked position. The lower endv of the lever 84 is preferably provided with a face 99 which bearsa ainst the upper surface of the bail 74 land exerts the desired amount of pressure thereon, this pressure being controlled by the threaded portion of the post 82.

In order to seal the to gle lever 84 against accidental unlocking which might result in accidental opening of the valve and partial discharge of the contents. the toggle lever 84 and the threaded post 82 are provided with holes 92 which re ister with the toggle lever in valve locking position and they may be sealed by means of a wire seal 94. Lifting up on the finger lever 88 to move the toggle lever 84 to unlocked positionshears the sealing wire thereby rendering the extinguisher instantly ready for emergency use and at thesame time providing a definite warning indication that the extinguisher may have been partially or fully discharged and should be reinspected or recharged.

The apertured end of the lever 60 is preferably positioned between a metal washer 96 and a resilient washer 98, the resilient washer 98 allowing the handle and plunger 32 to be moved downwardly by the sealing pressure exerted by the toggle lever 84, while the handle 60 is held in position by the nut 66 which may also serve to adjust the pressure exerted on the rod'32 by the toggle sealing lever 84.

The external and downwardly depending sides of the toggle lever, 84 are preferably closely fitted to the flat sides of the threaded posts 82, thereb improving the shearing action on the wire seal 94, and permitting the toggle lever 84 to serve as a handy wrench for adjustment of the position of the threadedpost 82. For this purpose the pivot pin 86 is formed as a removable and threaded pin, and when removed the toggle lever 84 may be used to turn the post 82 if the bail 14 has been movedfree of the post 82. Pin is secured to the nozzle member [8 by means of a flexible chain, I00 so that if either of them remains on the assembly 14 the portion I06 a dangerously low pressure which might render the extinguisher ineffective.

In order to guard against the possibility of explosion in case an extinguisher was allowed to remain in a. burning building, or otherwise exposed to excessive heat which might cause a dangerous increase in the pressure Within the bottle, a plug H0 having a fusible plug H2 is threaded into the assembly [4 and communicates directly with the interior of the bottle [0 by means of a fine passageway I M. The fusible plug H2 may be made of suitable alloy to allow it to melt at any desired temperature, for'instanceabout 165 F., thereby opening the bore in the plug H0 and allowing the gas pressure Within the bottle fully to escape to the atmosphere before the bottle has beenheated sufficiently to create a dangerous internal pressure.

The bottle is normally charged about threefourths full with a dry, free-flowing extinguishing powder such as a special grade of sodium bicarbonate mixed with other ingredients, and the gas is usually nitrogen or carbon dioxide at approximately 850 pounds pressure per square inch. Under these conditions, and assuming that the bottle became heated to approximately 170 F. before the fusible plug H2 released, the pressure within the bottle would be approximately 410 pounds, or well within the safety limits of the bottle. 7

In the operation of the bottle the hand engaged levers 60 and B8 are grasped and pressed together after the toggle lever 84 has been moved to unlocked position cutting the seal wire 94. As the handle 60 is depressed the valve plunger 32 is raised and a powerful stream of gas-propelled dry powder issues from the nozzle l8 and may be directed at the fire so long as the handle 60 is depressed.

The invention in its broader aspects is not limited to the specific mechanism shown and described but departures may be made therefrom within the scope of, the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

What is claimed is:

1. In a dry chemical fire extinguisher having a pressure bottle to be charged with dry powder and a. propellant gas under pressure and having a threaded aperture in one end thereof, the combination of a valved nozzle assembly having a threaded portion to close said aperture and control the fiow of gas and powder from the bottle to the nozzle and comprising a, body portion having a valve seat formed therein, a plunger carrying a valve closing disc, a spring urging the plunger to valve "closing position, means for moving the plunger'to valve opening position, a bail overlying the outer end of the plunger and engageable therewith for increasing the pressure with which the valve plunger is seated and means for releasably locking the bail in plunger seating position said locking means including a post threaded in said body portion and variably positionable to vary the pressure with which the bail engages the plunger.

2. A dry chemical fire extinguisher as claimed in claim 1 in which the bail is pivoted and one end is bifurcated to fit over the threaded post, and a toggle lever is pivotally mounted on the post to releasably engage the bail and press it against the plunger, said post and lever forming the bail locking means.

3. A dry chemical fire extinguisher as claimed in claim 2 in which the plunger lifting means comprises a lever pivoted on the body portion and engaging the plunger between the bail and body portion.

4. A dry chemical fire extinguisher as claimed in claim 1 in which the plunger lifting means comprises a lever pivoted on the body portion and engaging the plunger between the bail and body portion.

5. A dry chemical fire extinguisher as claimed in claim 1 in which the plunger is mounted for axial movement in a straight bore and a passage communicates between the valve seat and the nozzle.

6. A dry chemical fire extinguisher as claimed in claim 1 in which a pressure gauge is mounted on the valved nozzle assembly and communicates directly with the interior of the bottle.

7. A dry chemical fire extinguisher as claimed in claim 1 in which the bail is pivoted and channelled to fit over and secure a nut threaded on the end of the plunger, the bail is bifurcated to fit over and prevent rotation of a threaded post having fiat sides, and a toggle lever is pivotally mounted on the post to releasably engage the bail and press it against the plunger, said post and lever forming a bail locking means.

8. A dry chemical fire extinguisher as claimed in claim 7 in which the lever and post are apertur'ed to receive a sealing wire.

PHILIP M. CARTER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,543,827 Doty June 30, 1925 2,067,829 Denne Jan. 12, 1937 2,454,621 Allen Nov. 23, 1948 

